Manufacturing method of semiconductor device

ABSTRACT

The yield of semiconductor devices is improved. In an upper die of a resin molding die including a pair of the upper die and a lower die, by lengthening the radius of the cross section of an inner peripheral surface of a second corner part facing an injection gate of a cavity more than that of the other corner part, a void contained in a resin in resin injection can be pushed out into an air vent without allowing the void to remain in the second corner part of the cavity. Consequently, the occurrence of the void in the cavity can be prevented and then the occurrence of the appearance defect of the semiconductor device can be prevented.

CROSS-REFERENCE TO RELATED APPLICATION

The disclosure of Japanese Patent Application No. 2011-3560 filed onJan. 12, 2011 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND

The present invention relates to a technology of manufacturingsemiconductor devices, and particularly, to a technology effective whenapplied to resin molding.

Patent Document 1 (Japanese Patent Laid-Open No. 1998-270602) disclosesa structure in which electronic parts mounted on a circuit substrate arecovered with a sealing layer including a thermoplastic resin, and amethod for forming the sealing layer by the thermoplastic resin.

SUMMARY

Recently, semiconductor devices have attempted to thin a gold wire(electroconductive wire) for cost reduction. A molding (resin sealing)process in the assembling of resin-sealed semiconductor devices tends tocause wire displacement in the resin sealing, due to thinning of a goldwire.

To prevent the wire displacement, a high-fluidity molding resin having alow viscosity in a melted state is adopted as a molding resin (sealingresin) used for the resin sealing. A high-fluidity molding resin, whichhas a low viscosity (which is soft), easily form a large resin burr(resin blowout) in the air vent of a resin molding die. When a largeresin burr is formed, the appearance of the semiconductor device may bedefective. Alternatively, in mounting the semiconductor device on amounting substrate, a large resin burr may fall on the substrate land(foot pattern) of the mounting substrate to cause defective conduction(mounting defect) between the semiconductor device and the mountingsubstrate.

To minimize the resin burr, the opening of the air vent is small.

The small opening of the air vent can prevent the resin burr and canhardly escapes the air.

As a result, a void tends to occur in a corner part near the air vent ofthe cavity. When the void remains in the die, a void is formed on thesurface of a sealing body and then the appearance of the semiconductordevice becomes defective. Consequently, the yield of the semiconductordevice lowers.

Particularly, the remaining of the void tends to occur near the air ventwhich is farthest from the injection gate of the molding resin.

FIGS. 29 and 30 show the structure of a resin molding die in acomparative example for resin molding of a semiconductor device forwhich the present inventor compared. Furthermore, FIGS. 31 to 34 showthe state of resin flow in a comparative example in resin sealing of thesemiconductor device for which the present inventor compared.

As shown in FIGS. 29 and 30, the resin molding die has a pair of anupper die 30 and a lower die 31. The upper die 30 has a runner 37 to bea resin flow path, a cavity 33 adjacent to the runner 37 via aninjection gate 32, and air vents 35 adjacent to the cavity 33. As shownin a partially enlarged cross-sectional view in FIG. 29, the opening ofthe air vent 35 has a height (H) of around 30 μm to prevent the resinburr as much as possible.

When the resin is sealed by using the resin molding die, as shown inFIGS. 31 and 32, a molding resin 34 is injected into the cavity 33 withan injection pressure of P via the injection gate 32, and proceedsinvolving a void 36 toward the air vent 35 which is farthest andopposite from the injection gate 32.

After that, as shown in FIGS. 33 and 34, most of voids 36 escape to theair vent 35 along a resin flow Q. When the opening of the air vent 35 issmall (when the height of the air vent is around 30 μm), the voids 36partially fails to escape and remain in the corner part 33 a of thecavity 33 in FIG. 31.

As a result, a void is formed at a corner part of the sealing body ofthe semiconductor device after the resin sealing. This causes adefective appearance and lowers the yield of the semiconductor device.

The Patent Document 1 (Japanese Patent Laid-Open No. 1998-270602) failsto refer to a problem that avoid remains in a die. This patent documentfails to disclose a size, such as a radius, of the cross section of theinner peripheral surface at the corner part of the cavity of the die.The document describes that all the corner parts of the cavity of thedie are processed so that each of them has a curved surface. If theradius of the cross section of the curved surface of the corner partbecomes longer, a surface for forming the air vent and then the openingof the air vent become small. The smaller the semiconductor device is,the more difficult providing the air vent is.

The present invention has been made in view of the above circumstances.One of the purposes is to provide a technology for preventing a void ina die and improving the yield of a semiconductor device.

Another purpose is to provide a technology for improving the quality ofa semiconductor device.

The description of the present specification and the accompanyingdrawings will clarify the other purposes and the new feature of thepresent invention.

The following outlines a typical invention among the inventionsdisclosed in the present application.

The manufacturing method of a semiconductor device in accordance with arepresentative embodiment is that of a semiconductor device having asealing body including an upper surface, and a first side surface onwhich an air vent resin is formed and which is adjacent to the uppersurface, the method having the steps of: (a) preparing a resin moldingdie on which a cavity corresponding to a shape of the sealing body isformed for at least one of a pair of a first die and a second die, andwhich includes an injection gate and an air vent adjacent to the cavity,(b) arranging a plate-shaped member with a semiconductor chip mountedbetween the first die and the second one, and clamping both the dieswith the semiconductor chip covered with the cavity, and (c) injecting asealing resin from the injection gate into the cavity to form thesealing body over the plate-shaped member. The cavity of the resinmolding die includes a corner part for forming an edge part of thesealing body including the first side surface corresponding to the airvent which is farthest from the injection gate, and the upper surface. Aradius of the cross section of an inner peripheral surface of the cornerpart of the cavity is larger than that of the other corner part of thecavity forming the other edge part of the sealing body.

The manufacturing method of a semiconductor device according to anotherrepresentative embodiment is that of a semiconductor device having asealing body including an upper surface, a first side surface on whichan air vent resin is formed and which is adjacent to the upper surface,and a second side surface which is adjacent to the upper surface and thefirst surface, the method having the steps of (a) preparing a resinmolding die on which a cavity corresponding to a shape of the sealingbody is formed for at least one of a pair of a first die and a secondone, and which includes an injection gate and an air vent adjacent tothe cavity, (b) arranging a plate-shaped member with a semiconductorchip mounted between the first die and the second die, and clamping boththe dies with the semiconductor chip covered with the cavity, and (c)injecting a sealing resin from the injection gate into the cavity toform the sealing body over the plate-like member. The cavity of theresin molding die includes a first corner part for forming a first edgepart of the sealing body including the first side surface correspondingto the air vent which is farthest from the injection gate, and thesecond side surface; and a second corner part for forming a second edgepart of the sealing body including the first side surface and the uppersurface. A radius of a cross section of an inner peripheral surface ofthe second corner part is larger than that of the first corner part.

The following explains briefly the effect acquired by the typicalinvention among the inventions disclosed in the present application.

The defective appearance of semiconductor devices can be prevented toimprove the yield of semiconductor devices.

Further, the quality of semiconductor devices can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a structure of the semiconductor device inaccordance with the embodiment 1 of the present invention;

FIG. 2 is a back view showing a structure of the semiconductor deviceshown in FIG. 1;

FIG. 3 is a cross-sectional view showing a structure cut along the A-Aline in FIG. 1;

FIG. 4 is a partially enlarged cross-sectional view showing a structureof the RB part in FIG. 1;

FIG. 5 is a partially enlarged cross-sectional view showing a structureof the RA part in FIG. 1;

FIG. 6 is a partially enlarged cross-sectional view showing a structureof the RC part in FIG. 1;

FIG. 7 is a flowchart showing an assembling process of the semiconductordevice in FIG. 1;

FIG. 8 is a plan view showing the assembling process from dicing to diebonding in FIG. 7;

FIG. 9 is a plan view showing the assembling process from wire bondingto molding in FIG. 7;

FIG. 10 is a plan view showing the assembling process from marking tosingulating in FIG. 7;

FIG. 11 is a partial cross-sectional view and a partially enlargedcross-sectional view showing a structure of a resin molding die used inthe molding of the assembling process in FIG. 7;

FIG. 12 is a transparent plan view showing a structure of a runner and acavity in the upper die of the resin molding die in FIG. 11;

FIG. 13 is a plan view showing a structure of the lower die of the resinmolding die in FIG. 11;

FIG. 14 is a partially enlarged cross-sectional view showing a structureof the rB part in FIG. 12;

FIG. 15 is a partially enlarged cross-sectional view showing a structureof the rA part in FIG. 12;

FIG. 16 is a partially enlarged cross-sectional view showing a structureof the rC part in FIG. 12;

FIG. 17 is a partial cross-sectional view showing a resin flow state inthe molding of the assembling process in FIG. 7;

FIG. 18 is a partial plan view showing the resin flow state in FIG. 17;

FIG. 19 is a partial cross-sectional view showing a resin fillingcompletion state in the molding of the assembling process in FIG. 7;

FIG. 20 is a partial plan view showing the resin filling completionstate in FIG. 19;

FIG. 21 is a cross-sectional view showing a modified structure of thesemiconductor device in accordance with the embodiment 1 of the presentinvention;

FIG. 22 is a plan view showing a modified structure of the semiconductordevice of an embodiment 2 of the present invention;

FIG. 23 is a back view showing a structure of the semiconductor deviceshown in FIG. 22;

FIG. 24 is a cross-sectional view showing a structure cut along the A-Aline in FIG. 22;

FIG. 25 is a flowchart showing an assembling process of thesemiconductor device in FIG. 22;

FIG. 26 is a plan view showing a modified structure of the semiconductordevice in accordance with the embodiment 2 of the present invention;

FIG. 27 is a back view showing a structure of the semiconductor devicein FIG. 26;

FIG. 28 is a cross-sectional view showing a structure cut along the A-Aline in FIG. 26;

FIG. 29 is a cross-sectional view and a partially enlargedcross-sectional view showing the structure of a resin molding die incomparative example;

FIG. 30 is a transparent plan view showing the structure of the runnerand the cavity of the upper die of the resin molding die in FIG. 29;

FIG. 31 is a partial cross-sectional view showing a resin flow state inmolding in comparative example;

FIG. 32 is a partial plan view showing the resin flow state in FIG. 31;

FIG. 33 is a partial cross-sectional view showing the resin fillingcompletion state in molding in FIG. 31; and

FIG. 34 is a partial plan view showing the resin filling completionstate in FIG. 33.

DETAILED DESCRIPTION

In embodiments below, except for cases particularly necessary, noexplanation of the same or similar parts is repeated as a rule.

Furthermore, the following embodiments will be explained, divided intosections or embodiments, if necessary for convenience. Except for thecase where it shows clearly in particular, they are not mutuallyunrelated and one has relationships such as a modification, details, andsupplementary explanation of some or entire of another.

Moreover, in the following embodiments, in referring to the number ofelements, (including the number, a numeric value, an amount, and arange), they should not be restricted to the specific number but may begreater or smaller than the specific number, except for the case wherethey are clearly specified in particular and where they are clearlyrestricted to a specific number theoretically.

In addition, in the following embodiments, an element (including anelement step) is not necessarily indispensable, except for the casewhere it is clearly specified in particular and where it is consideredto be clearly indispensable theoretically.

Furthermore, in the following embodiments, phrases “consisting of A,”“constituted of A,” “having A” and “including A” include other elements,except for the case where it is clearly specified in particular to berestricted to the element. Similarly, in the following embodiments, whenshape and position relationship of an element are referred to, whatresembles or is similar to the shape, etc. shall be included, except forthe case where it is clearly specified in particular and where it isconsidered to be clearly not right theoretically. This statement alsoapplies to the numeric value and range described above.

Embodiments of the present invention are explained in detail inaccordance with the drawings. In all the drawings for explainingembodiments, the same symbol is attached to the members having the samefunction, and its repeated explanation is omitted.

(Embodiment 1)

FIG. 1 is a plan view showing a structure of the semiconductor device inaccordance with the embodiment 1 of the present invention. FIG. 2 is aback view showing a structure of the semiconductor device shown inFIG. 1. FIG. 3 is a cross-sectional view showing a structure cut alongthe A-A line in FIG. 1. FIG. 4 is a partially enlarged cross-sectionalview showing a structure of the RB part in FIG. 1. FIG. 5 is a partiallyenlarged cross-sectional view showing a structure of the RA part inFIG. 1. FIG. 6 is a partially enlarged cross-sectional view showing astructure of the RC part in FIG. 1.

The semiconductor device in accordance with the embodiment 1 in FIGS. 1to 3 is a substrate semiconductor package in which a semiconductor chip1 mounted on an upper surface 2 a of a wiring substrate 2 is sealed withresin by a sealing body 4 and is electrically connected to the wiringsubstrate 2 via a wire (electroconductive wire) 7. The semiconductorchip 1 is mounted on the wiring substrate 2 and is connected to thewiring substrate 2 via a wire 7. The resin sealing body 4 seals thesemiconductor chip 1 and wires 7.

In the embodiment 1, as a substrate semiconductor device, a BGA 9 withsolder balls 5, which are external terminals, aligned on a lower surface2 b of the wiring substrate 2 in a grid pattern as shown in FIG. 2, isexplained.

The semiconductor chip 1 mounted on the BGA 9 incorporates asemiconductor integrated circuit. As shown in FIG. 3, the semiconductorchip 1 is adhered to the upper surface 2 a of the wiring substrate 2 bya die bonding member 6 such as a resin paste member. Electrode pads isare formed on a main surface 1 a of the semiconductor chip 1. Wires 7electrically connect these electrode pads and bonding leads 2 c, whichare ones of the wiring substrate 2 (see FIG. 8).

Accordingly, the electrode pads 1 c are connected to the solder balls 5,which are external terminals of the BGA 9, via the wire 7, the bondinglead 2 c, and the wiring parts of wiring substrate 2.

In this example, the semiconductor chip 1 is formed by silicon. In thisexample, the wire 7 is a gold or copper wire. The wire 7 has a diameterof φ20 μm or less. The sealing resin 3 (see FIG. 17), which is a resinfor forming the sealing body 4, is a thermosetting epoxy resin. Theexternal terminal is the solder ball 5 using a solder member.

The BGA 9 is a semiconductor package assembled by resin molding usingtransfer molding in the molding (sealing) of the assembling process.

The sealing body 4 has a shape corresponding to the cavity 14 a of theresin molding die 13 in FIG. 11 used in the molding. The upper surface 4a of the sealing body 4, each of its adjacent side surfaces, and eachedge part including the upper surface 4 a and each of its adjacent sidesurfaces have shapes corresponding to shapes of each place (each cornerpart and each inner peripheral surface) of the cavity 14 a.

The sealing body 4 has a gate resin 4 i and an air vent resin 4 j inFIG. 3. These resins are formed when the sealing resin 3 remains in theinjection gate 14 d and the air vent 14 h of the resin molding die 13.

A second edge part 4 f (an RB part), which includes the first sidesurface 4 b and the upper surface 4 a arranged at an angle part 4 hfacing the gate resin as shown in FIG. 1, has a curved cross sectionhaving a radius R2 as shown in FIG. 4. A first edge part 4 e(an RApart), which includes a first side surface 4 b and a second side surface4 c adjacent to the first side surface 4 b as shown in FIG. 1, has acurved cross section having a radius R1 as shown in FIG. 5. A third edgepart 4 g (an RC part), which includes the second side surface 4 c andthe upper surface 4 a as shown in FIG. 1 has a curved cross sectionhaving a radius R3 as shown in FIG. 6. The first edge parts 4 e, thesecond edge part 4 f, and the third edge part 4 g have shapescorresponding to the shapes of the corner parts of the cavity 14 a.

The cross sections of the edge parts (the second edge part 4 f and thethird edge part 4 g) in FIGS. 4 and 6 are obtained by cutting thesealing body 4 in a direction along the height of BGA 9. The crosssections of the first edge part 4 e in FIG. 5 is obtained by cutting thesealing body 4 along a crossing direction of the height of the BGA 9.

In the BGA 9 of the embodiment 1, the radius R2 of the cross section ofthe second edge part 4 f is longer than the radius R1 of that of thefirst edge part 4 e (the radius R2>the radius R1). The radius R3 of thecross section of the third edge part 4 g is longer than the radius R1 ofthat of the first edge part 4 e (the radius R3>the radius R1). Theradius R2 of the cross section of the second edge part 4 f has the sameradius as the radius R3 of that of the third edge part 4 g (the radiusR2=the radius R3).

The sealing body 4 in FIG. 1 has the third side surface 4 d formed on aposition corresponding to the one over the injection gate 14 d of theresin molding die 13 in FIG. 11. The gate resin 4 i projects from thethird side surface 4 d. The first side surface 4 b facing the third sidesurface 4 d is a side surface formed at the angle part 4 h which isfarthest from the gate resin 4 i.

The sealing body 4 has the third side surface 4 d which is adjacent tothe second side surface 4 c and the upper surface 4 a, which areadjacent to the first side surface 4 b, and faces the first side surface4 b. The third side surface 4 d is formed over the injection gate 14 dof the resin molding die 13.

In a planar view of the sealing body 4 in FIG. 1, fourth side surfaces 4k are formed on two of the four angle parts 4 h (not on the first sidesurface 4 b and the third side surface 4 d). The fourth side surfaces 4k face each other.

The air vent resin 4 j projects from the first side surface 4 b and thetwo fourth side surfaces 4 k.

In a planar view of the sealing body 4, the four side surfaces betweenthe angle parts 4 h are the second side surfaces 4 c. The two sidesurfaces between the first side surface 4 b and the fourth side surface4 k are the second side surfaces 4 c. So are the two side surfacesbetween the third side surface 4 d and the fourth side surface 4 k.

Among four edge parts having the second side surface 4 c and the uppersurface 4 a, the edge parts (the RE part, the RG part, and the RI part)other than the third edge part 4 g (the RC part) have the same crosssection as that of the third edge part 4 g with the radius R3 in FIG. 6.Each of the curved planes of the cross sections has the radius R3.

The edge parts for the upper surfaces 4 a of the four angle parts 4 h(the RD part, the RF part, and the RH part) other than the second edgepart 4 f (the RB part) have the same cross section as that of the secondedge part 4 f with the radius R2 in FIG. 4. Each of the curved planes ofthe cross sections has the radius R2.

The edge parts for side surfaces of four angle parts 4 h (an RK part, anRL part, an RM part, an RN part, an RP part, an RQ part, and an RJ part)other than the first edge part 4 e (RA part) have the same cross sectionas that of the first edge part 4 e with the radius R1 in FIG. 5. Each ofthe curved planes of the cross sections has the radius R1.

As described above, the eight edge parts (the RB part, the RD part, theRF part, the RH part, the RC part, the RE part, the RG part, and the RIpart) relating to the upper surface 4 a in the sealing body 4 have across section with the radius R2 in FIG. 4 or the radius R3 in FIG. 6.The eight edge parts (the RA part, the RK part, the RL part, the RMpart, the RN part, the RP part, the RQ part, and the RJ part) relatingto the side surface have a cross section with the radius R1 in FIG. 5.The radius R2 is as long as the radius R3. They are longer than theradius R1 (R2=R3>1).

Next, the manufacturing method of the BGA (semiconductor device) 9 ofthe embodiment 1 is explained.

FIG. 7 is a flowchart showing an assembling process of the semiconductordevice in FIG. 1. FIG. 8 is a plan view showing the assembling processfrom dicing to die bonding in FIG. 7. FIG. 9 is a plan view showing theassembling process from wire bonding to molding in FIG. 7. FIG. 10 is aplan view showing the assembling process from marking to singulating inFIG. 7.

First, dicing shown at Step S1 in FIGS. 7 and 8 is performed. As shownin FIG. 8, cutting is performed along dicing line 8 a of a semiconductorwafer 8. Then, semiconductor chips 1 with good quality are selected andobtained.

After that, die bonding shown at Step S2 in FIGS. 7 and 8 is performed.

First, a plural piece substrate 10, which is a plate-shaped memberhaving multiple device regions 10 c in FIG. 8 is prepared. Then,semiconductor chips 1 having electrode pads 1 c formed on each mainsurface 1 a are mounted on multiple device regions 10 c of the uppersurface 10 a of the multiple piece substrate. The semiconductor chip 1is adhered to the plural piece substrate 10 via the die bonding member 6in FIG. 3 such as a resin paste member.

After that, wire bonding shown at Step S3 in FIGS. 7 and 9 is performed.Plural electrode pads is of the semiconductor chip 1 are electricallyconnected with plural bonding leads 2 c of the plural piece substrate 10with the wire 7, which is an electroconductive wire. A gold wire isused. It is thin and has a diameter of φ20 μM or less.

After the wire bonding, molding shown at Step S4 in FIGS. 7 and 9 isperformed. In the molding of the embodiment 1, resin sealing by atransfer molding method is explained. Resin sealing is performed by thetransfer molding method in the plural piece substrate 10 in which theelectrode pad 1 c of the semiconductor chip 1 is connected electricallywith the bonding lead 2 c of the device region 10 c by the wire bonding.

The structure of the resin molding die used in the molding in accordancewith the embodiment 1 is explained.

FIG. 11 is a partial cross-sectional view and a partially enlargedcross-sectional view showing a structure of the resin molding die usedin the molding of the assembling process in FIG. 7. FIG. 12 is atransparent plan view showing a structure of a runner and a cavity inthe upper die of the resin molding die in FIG. 11. FIG. 13 is a planview showing a structure of the lower die of the resin molding die inFIG. 11. FIG. 14 is a partially enlarged cross-sectional view showing astructure of the rB part in FIG. 12. FIG. 15 is partially enlargedcross-sectional view showing a structure of the rA part in FIG. 12. FIG.16 is a partially enlarged cross-sectional view showing a structure ofthe rC part in FIG. 12. FIG. 17 is a partial cross-sectional viewshowing a resin flow state in the molding of the assembling process inFIG. 7. FIG. 18 is a partial plan view showing the resin flow state inFIG. 17. FIG. 19 is a partial cross-sectional view showing a resinfilling completion state in the molding of the assembling process inFIG. 7. FIG. 20 is a partial plan view showing the resin fillingcompletion state in FIG. 19.

The resin molding die 13 in FIG. 11 includes a pair of the upper die 14,which is a first die, and the lower die 15, which is a second die. Inthe resin filling, a mating face 14 c of the upper die 14 and a matingface 15 b of the lower die 15 are mated and clamped. After that, resinis supplied to the cavity 14 a to perform the filling.

On the upper die 14, the cavity 14 a for forming the sealing body 4 ofthe BGA 9 in FIG. 1 is formed. Furthermore, the injection gate 14 dconnected with the cavity 14 a and the air vent 14 h connected with thecavity 14 a are formed. And, a cull 14 k and a runner 14 m to be a flowpath of the resin are provided. The cull 14 k, the runner 14 m, theinjection gate 14 d, the cavity 14 a, and the air vent 14 h areconnected with each other. The air vent 14 h in FIG. 11 is an air outletfacing the injection gate 14 d. As shown in FIG. 12, on other twocorners in the plan view of the cavity 14 a, an air vent 14 i and an airvent 14 j connected with the cavity 14 a are formed.

FIG. 12 shows shapes of the runner 14 m, the injection gate 14 d, thecavity 14 a and air vents 14 h, 14 i and 14 j, seen through the upperdie 14 in FIG. 11 from the above.

As shown in FIGS. 11 and 13, a concave substrate mounting part 15 a forarranging the substrate and a pot 15 c are formed on the lower die 15. Aplunger head 15 d and a plunger rod 15 e for pushing out the resin arearranged in the pot 15 c.

Next, a detailed shape of the cavity 14 a of the upper die 14 isexplained.

In the upper die 14, the size of the radius of the cross section of theinner peripheral surface 14 b (inner peripheral surface 14 b (size ofcurvature radius of curved plane)) of the corner parts of the cavity 14a is characterized.

In FIG. 12, a first corner part 14 e (rA) of the cavity 14 a forming afirst edge part 4 e (including first side surface 4 b and second sidesurface 4 c) of the sealing body 4 in FIG. 1 at a position correspondingto the air vent 14 h which is farthest from the injection gate 14 d ofthe upper die 14 is formed, as shown in FIG. 15, so that the crosssection, of the inner peripheral surface 14 b has a radius of r1. Asecond corner part 14 f (rB) of the cavity 14 a in FIG. 12 forming thesecond edge part 4 f (including first side surface 4 b and upper surface4 a) of the sealing body 4 shown in FIG. 1 is formed so that the crosssection of the inner peripheral surface 14 b has a radius of r2 as shownin FIG. 14. The radius r2 of the cross section of the second corner part14 f of the cavity 14 a is longer than the radius r1 of that of thefirst corner part 14 e (r2>r1).

Furthermore, a third corner part 14 g (rC) of the cavity 14 a in FIG. 12forming the third edge part 4 g (including the second side surface 4 cand upper surface 4 a) of the sealing body 4 shown in FIG. 1 is formedso that the cross section of the inner peripheral surface 14 b has aradius of r3 as shown in FIG. 16. The radius r3 of the cross section ofthe third corner part 14 g of the cavity 14 a is formed, as is the casefor the second edge part 4 f, longer than the radius r1 of that of thefirst corner part 14 e (r3>r1).

The radius r2 of the cross section of the second corner part 14 f is thesame as the radius r3 of that of the third corner part 14 g (r2=r3).

In the cavity 14 a in FIG. 12, all cross sections of the innerperipheral surface 14 b of the corner parts (the rB part, the rC part,the rD part, the rE part, the rF part, the rG part, the rH part, and therI part) of the cavity 14 a forming edge parts including respective sidesurfaces and upper surfaces 4 a of the sealing body 4 shown in FIG. 1are formed with the size of the radius r2 shown in FIG. 14 (also may bethe radius r3 in FIG. 16).

Further, in the cavity 14 a in FIG. 12, all cross sections of the innerperipheral surface 14 b of corner parts (the rA part, the rJ part, therK part, the rL part, the rM part, the rN part, the rP part, and the rQpart) of the cavity 14 a forming edge parts including side surfaces ofthe sealing body 4 in FIG. 1 are formed with the radius r1 shown in FIG.15 (r1<r2).

In the cavity 14 a, the reason why the radius r1 of cross sections ofinner peripheral surfaces 14 b of the corner parts (the rA part, the rJpart, the rK part, the rL part, the rM part, the rN part, the rP part,and the rQ part) of the cavity 14 a forming the edge parts including theside surfaces (the edge parts in which adjacent side surfaces cross eachother) is shorter than the radius r2 is to keep air vents 14 h, 14 i and14 j. When a radius r of the cross section of the inner peripheralsurface 14 b of the corner part of the cavity 14 a forming the edge partincluding side surfaces arranged for the angle part 4 h of the sealingbody 4 is long, because the area of the side surface (for example, firstside surface 4 b) of the angle part 4 h of the sealing body 4 is small,the side surface becomes a curved plane not to allow the air vents, tobe formed at the corner part of the cavity 14 a.

Accordingly, by shortening the radius r1 than the radius r2 (r1<r2), airvents 14 h, 14 i and 14 j can be formed at the corner parts other thanthe corner part arranged with the injection gate 14 d of the cavity 14a.

In the cavity 14 a, the radius r2 of the cross section of the innerperipheral surface 14 b of the second corner part 14 f of the cornerpart which is farthest from the injection gate 14 d should preferably be0.5 mm or more.

In the second corner part 14 f of the cavity 14 a, the radius r2 of thecross section of the inner peripheral surface 14 b was set to be 0.25,0.45, 0.60, or 0.75 to investigate the rate of void occurrence. The rateof void occurrence was 1% only when r2 is 0.25. It was 0% in othercases. Due to this reason, the radius r2 should preferably be set to be0.5 mm or more in consideration of variation in mass production.

In the molding of the embodiment 1, the resin sealing is performed byusing a high-fluidity resin as the sealing resin 3. In the assembling ofthe BGA 9, a gold wire (wire 7) with a thickness f φ20 μm or less isused for the cost reduction. Since the wire displacement occurs easilyin the resin filling in the molding, the high-fluidity resin is adoptedas the sealing resin 3 to reduce the wire displacement.

The following explains the definition of the high-fluidity resin to beadopted as the sealing resin 3 in the molding in accordance with of theembodiment 1. The high-fluidity resin preferably has a spiral flow of100 cm or more, which represents the properties of the resin.

The spiral flow shows the arrival length (flow length) of the resin inthe groove when a resin is filled into a test die provided with a groovein a spiral shape (eddy shape) under a definite condition. The larger(longer) the numerical value of the spiral flow, the higher the fluidityof the resin. Accordingly, the spiral flow can evaluate the fluidity ofthe resin in injection molding.

In the measurement of the spiral flow, a die and an injection moldingmachine prescribed in EMMI-1-66 are used as a measuring apparatus. Thesample to be measured is taken out of a reserving chamber, left in asealed state under room temperature for two hours. Then, the sample isunsealed to be measured. The test is completed within two hours afterthe unsealing.

As the measurement condition, the quantity of the sample is 15 g, andthe cull thickness is about 3 mm. The injection pressure is 6.9±0.5 Mpa.The molding time is 120±5 seconds without carrying out preheat. Thetemperature is 175±2° C. Under these conditions, the temperature reachesthe prescribed level. Then, the sample is embedded and the plunger islet down rapidly to start pressurization within 10 seconds.

Then, the spiral flow can be measured by disassembling the die after thelapse of the prescribed time and reading the flow length (cm) of theresin.

Ordinary resins have the spiral flow of around 90 cm. But, theembodiment 1 adopts a high-fluidity resin having a spiral flow of 100 cmor more as the sealing resin 3. This can prevent the wire displacementeven when the diameter of the wire 7 is φ20 μm or less.

When the high-fluidity resin as described above is used, the resinenters the air vents adjacent to the cavity 14 a in the resin filling.Then, the resin burr tends to occur.

Accordingly, to minimize such the occurrence of resin burr, in theembodiment 1, as shown in FIG. 11, the height H of the opening of theair vent 14 h (the same for air vents 14 i, 14 j shown in FIG. 12) ofthe resin molding die 13 used in the molding process is changed fromconventional value (around 40 μm) to around 30 μm.

As described above, setting the opening height of the air vent 14 h toaround 30 μm can minimize the occurrence of resin burr when thehigh-fluidity resin is used.

Next, the following explains the resin sealing method in accordance withthe embodiment 1 in detail.

First, as shown in FIG. 17, the plural piece substrate 10 mounted withthe semiconductor chip 1 is sent between the upper die 14 and the lowerdie 15. Then, the plural piece substrate 10 is arranged in the concavesubstrate mounting part 15 a of the lower die 15.

After that, the dies are clamped so that the mating surface 14 c of theupper die 14 and the mating surface 15 b of the lower die 15 are mated,and, in the state where the semiconductor chip 1 is covered with thecavity 14 a of the upper die 14, as shown in FIGS. 17 and 18, thesealing resin 3 is injected into the cavity 14 a from the injection gate14 d with an injection pressure S. The sealing resin 3 heated and meltedin the pot 15 c of the lower die 15 shown in FIG. 13 is pushed out bythe plunger head 15 d to be fed to the cavity 14 a.

The sealing resin 3 used is the described high-fluidity resin.

The sealing resin 3 pushed out into the cavity 14 a via the injectiongate 14 d proceeds toward the air vent 14 h facing the injection gate 14d, while dispersing in a radial pattern with plural voids (air bubbles)12 contained in the resin.

Since the radius r2 of the cross section of the inner peripheral surface14 b of the corner part (second corner part 14 f) corresponding to theair vent 14 h which is farthest from the injection gate 14 d of thecavity 14 a is 0.5 mm or more, the void 12 does not remain in the secondcorner part 14 f. The void 12 is transported to the corner part of thecavity 14 a by a resin flow T in FIG. 19. Then, the void 12 is pushedout into the air vent 14 h.

As a result, the sealing resin 3 can be filled as shown in FIG. 20without the void 12 remained in the cavity 14 a.

Consequently, the sealing body 4 shown in FIG. 1 is formed over theplural piece substrate 10. Since no void 12 remains in the cavity 14 a,no void is formed on the surface of the sealing body 4 to cause nodefective appearance.

Consequently, the molding shown at Step S4 in FIGS. 7 and 9 ends.

After the resin molding, the marking shown at Step S5 in FIGS. 7 and 10is performed. As shown in FIG. 10, an intended mark 11 is marked on thesurface of the sealing body 4.

After that, ball mounting shown at Step S6 in FIGS. 7 and 10 isperformed. On the lower surfaces 10 b side in FIG. 7 of plural deviceregions 10 c of the plural piece substrate 10 in FIG. 10, plural solderballs 5, which are external terminals, are mounted. Reflow melts thesolder balls 5. Then, the solder balls 5 are bonded electrically to theplural electrodes of the lower face 10 b of the plural piece substrate10.

After ball mounting, singulating shown at Step S7 in FIGS. 7 and 10 isperformed. The plural piece substrate 10 is cut by dicing to besingulated into the individual BGA 9. Consequently, the assembling ofthe BGA 9 in FIGS. 1 to 3 ends.

According to the manufacturing method of the semiconductor device (BGA9) in accordance with the embodiment 1, by lengthening the radius r2 ofthe cross section of the inner peripheral surface 14 b of the cornerpart (second corner part 14 f) facing the injection gate 14 d of thecavity 14 a, the void 12 contained in the resin can be pushed out intothe air vent 14 h in the injection, without the void remained in thecorner part of the cavity 14 a.

In the resin molding die 13, by lengthening the radius r2 of the crosssection of the inner peripheral surface 14 b of the corner part (secondcorner part 14 f over air vent 14 h facing injection gate 14 d) which isfarthest from the injection gate 14 d of the cavity 14 a more than theradius r1 of that of the inner peripheral surface 14 b of the cornerpart (first corner part 14 e) forming the edge part including sidesurfaces of the sealing body 4, the void 12 contained in the injectionof the sealing resin 3 (high-fluidity resin) can be pushed out into airvents 14 h, 14 i and 14 j, without the void remained in the corner partsof the cavity 14 a, particularly in the second corner part 14 f, too,which easily allows the void 12 to remain.

Consequently, the occurrence of the void 12 can be prevented in thecavity 14 a. Then, the formation of the void can be prevented in thesealing body 4.

As a result, the occurrence of the appearance defect can be prevented inthe BGA 9 (semiconductor device). Then, the yield of the BGA 9 improves.

Since the occurrence of the appearance defect of the BGA 9 can beprevented in the BGA 9, the yield of the BGA 9 can improve.

Moreover, by lengthening the radius r2 of the cross section of the innerperipheral surface 14 b of the second corner part 14 f over the air vent14 h which is farthest from the injection gate 14 d of the cavity 14 amore than the radius r1 of that of the first corner part 14 e, which isthe corner part of the cavity 14 a forming the edge part including sidesurfaces of the sealing body 4, the mold-releasing properties when thesealing body 4 is released from the die can be improved.

Meanwhile, when the radius r1 of the first corner part 14 e is longer(when the radius r1 is as long as the radius r2), the curved plane islarge in the corner part of the cavity 14 a and the formation of the airvents is difficult. But, in the embodiment 1, by shortening the radiusr1 of the cross section of the inner peripheral surface 14 b of thefirst corner part 14 e more than the radius r2 of that of the secondcorner part 14 f (radius r1<radius r2), the air vents can be formed.

And, by setting the radius r2 of the cross section of the innerperipheral surface 14 b of the second corner part 14 f over the air vent14 h which is farthest from the injection gate 14 d of the cavity 14 ato be the same length as the radius r3 of that of the third corner part14 g continued to the second corner part 14 f, shaving with the sameshaving blade becomes possible in forming the cavity 14 a. Since thisallows to perform the processing of the inner peripheral surface 14 bcontinuously with the same shaving blade without changing the shavingblade, the time for fabricating the die can be shortened as comparedwith a case that the radius r2 and the radius r3 differ in size.

Since the semiconductor device in accordance with the embodiment 1 usesa thin gold wire with a diameter of φ20 μm or less, as compared withcases that a gold wire with a diameter of more than φ20 μm is used, theusage quantity of gold is reduced and the material cost can be reduced.

Regarding the use of a thin gold wire of φ20 μm or less as the wire 7,the wire displacement can reduce because a high-fluidity resin isadopted as the sealing resin 3.

Regarding the adoption of the mentioned high-fluidity resin as thesealing resin 3, the occurrence of the resin burr can be minimizedbecause the opening height (H) of the air vents adjacent to the cavity14 a is around 30 μm.

Next, a modified embodiment 1 is explained.

FIG. 21 is a cross-sectional view showing the structure of asemiconductor device in accordance with the modified embodiment 1 of thepresent invention. In this example, the semiconductor device is an LGA(Land Grid Array) 16.

The LGA 16 is, like the BGA 9, a substrate semiconductor device mountedwith the semiconductor chip 1 over the wiring substrate 2. Landterminals 2 d to be external terminals are arranged in a grid patternfor a lower face 2 b of the wiring substrate 2. In the LGA 16, too, thesemiconductor chip 1 and plural wires 7 are sealed with resin by thesealing body 4. The forming method of the sealing body 4 is exactly thesame as that of the sealing body 4 of the BGA 9.

In the molding of the assembling of the LGA 16, the resin sealing isperformed by using the die shown in FIGS. 11 to 16. In the filling ofthe resin, states shown in FIGS. 17 to 20 allow to push out the void 12contained in the resin into air vent without allowing the void to remainin corner parts of the cavity 14 a.

Consequently, like in the BGA 9, the occurrence of the void 12 can beprevented in the cavity 14 a. The formation of the void can be preventedin the sealing body 4.

As a result, the occurrence of the appearance defect of the LGA 16(semiconductor device) can be prevented. The yield of the LGA 16 canimprove. Moreover, the quality of the LGA 16 can improve because theoccurrence of the appearance defect of the LGA 16 can be prevented.

Other effects given by the LGA 16 are the same as effects of the BGA 9.The repeated explanation is omitted.

(Embodiment 2)

FIG. 22 is a plan view showing a structure of the semiconductor devicein accordance with an embodiment 2 of the present invention. FIG. 23 isa back view showing a structure of the semiconductor device in FIG. 22.FIG. 24 is a cross-sectional view showing a structure cut along the A-Aline in FIG. 22. FIG. 25 is a flowchart showing an assembling process ofthe semiconductor device in FIG. 22.

The embodiment 2 explains a manufacturing method of a flamesemiconductor device assembled by using a lead frame (plate-like member)21 in FIG. 25. The embodiment 2 mentions picking up a QFP (Quad FlatPackage) 20 with resin sealed.

The structure of the QFP 20 is explained using FIGS. 22 to 24. The QFP20 has the semiconductor chip 1 in which a semiconductor integratedcircuit is formed, plural inner leads (lead) 21 b arranged in a radialpattern around the semiconductor chip 1, plural outer leads 21 c formedtogether with the inner lead 21 b, and plural wires 7 connectingelectrically an electrode pad 1 c being a surface electrode formed forthe main surface 1 a of the semiconductor chip 1 with the inner lead 21b corresponding to the electrode pad 1C.

Furthermore, the QFP 20 has a die pad (also called a tab) 21 a being achip mounting part having the semiconductor chip 1 fixed via such diebonding member 6 as silver paste; and the sealing body 4 that is formedfrom a sealing resin by the resin sealing and seals the semiconductorchip 1, the die pad 21 a, plural wires 7, and plural inner leads 21 b.

Because of being the QFP 20, plural outer leads 21 c formed togetherwith plural inner leads 21 b project from the side surface of thesealing body 4 toward the outside in four directions, and outer leads 21c are bent in a gull-wing shape.

Because the QFP 20 is a wire bonding package as shown in FIG. 24, thesemiconductor chip 1 mounted over the die pad 21 a is mounted face-upwith the main surface 1 a upward. Accordingly, the die pad 21 a isbonded with the rear surface 1 b of the semiconductor chip 1 via the diebonding member 6. Furthermore, each of plural electrode pads 1 c formedfor the main surface 1 a is connected electrically with the inner lead21 b via the wire 7. Consequently, the semiconductor chip 1 is connectedelectrically with the inner lead 21 b and the outer lead 21 c to be anexternal terminal.

Plural wires 7 can be gold or copper.

The inner lead 21 b, the outer lead 21 c, and the die pad 21 a areformed by a thin plate-shaped member including a copper alloy and aniron-nickel alloy. The sealing body 4, which includes a thermosettingepoxy-based resin, is formed by the resin sealing.

The sealing body 4 is formed by the resin molding die 22 as shown inFIG. 25, like the sealing body 4 of the BGA 9 in accordance with theembodiment 1.

Next, the assembling process of the semiconductor device (QFP 20) inaccordance with the embodiment 2 is explained along the manufacturingflowchart in FIG. 25.

First, dicing shown at Step S11 in FIG. 25 provides the semiconductorchip 1 with a good quality.

After that, the die bonding shown at Step S12 is performed. As shown inFIG. 24F, the semiconductor chip 1 is mounted via the die bonding member6 on the die pad 21 a of the lead frame 21. The die bonding member 6bond the rear surface 1 b of the semiconductor chip 1 and the die pad 21a.

Next, the wire bonding shown at Step S13 is performed. As shown in FIG.24, the electrode pad 1 c of the main surface 1 a of the semiconductorchip 1 is connected electrically with inner lead 21 b corresponding tothe electrode pad 1 by using the wire 7. The wire 7 can be gold orcopper.

Subsequently, the molding shown at Step S14 is performed. In the moldingin accordance with the embodiment 2, the resin sealing like that in theembodiment 1 performed by using the resin molding die 22 in whichcavities 14 a and 15 f are formed on both the upper die 14 and the lowerdie 15.

Concerning the cavity 14 a of the upper die 14 of the resin molding die22 in FIG. 25, the shape of corner parts of the inner peripheral surface14 b (see FIGS. 14 to 16) is the same that in accordance with theembodiment 1 in FIGS. 11 to 16.

Accordingly, in the resin filling during the molding of the QFP 20, too,the same state as the state in FIGS. 17 to 20 is created in the cavity14 a of the upper die 14 arranged with the semiconductor chip 1. Theresin filling is performed while pushing out the void 12 contained inthe resin into air vents without allowing the void to remain in cornerparts and the sealing body 4 is formed.

After the resin molding ends, the marking at Step S15 is performed forthe intended mark 11 (see FIG. 10) to the sealing body 4. After that,the singulating at Step S16 is performed to end the assembling of theQFP 20. In the singulating, along with the cutting outer leads 21 c, thebending into the gull-wing shape is performed.

In the manufacturing method of the QFP 20 of the embodiment 2, too, inthe resin filling during the molding, the same state as the resinflowing state in FIGS. 17 to 20 can be created, and the void 12contained in the resin can be pushed out into respective air ventwithout allowing the void to remain in corner part of the cavity 14 a.

Consequently, like in the embodiment 1, the occurrence of the void 12can be prevented in the cavity 14 a (15 f). The formation of the voidcan be prevented in the sealing body 4.

As a result, like in the QFP 20 (frame semiconductor device), too, theoccurrence of the appearance defect of the QFP 20 can be prevented, andthe yield of the QFP 20 can improve. Moreover, because the occurrence ofthe appearance defect of the QFP 20 can be prevented, the quality of theQFP 20 can improve.

Because other effects given by the QFP 20 are the same as the effect ofthe BGA 9 in the embodiment 1. The repeated explanations are omitted.

Next, a modified embodiment 2 is explained.

FIG. 26 is a plan view showing the modified structure of thesemiconductor device in accordance with the embodiment 2 of the presentinvention. FIG. 27 is a back view showing a structure of thesemiconductor device in FIG. 26. FIG. 28 is a cross-sectional viewshowing a structure cut along the A-A line in FIG. 26.

The modified example of the embodiment 2 shown in FIGS. 26 to 28 is acase that the semiconductor device is a QFN (Quad Flat Non-leadedPackage) 23.

Similarly to the QFP 20, the QFN 23 is a frame semiconductor deviceassembled by using the lead frame 21 in FIG. 25. The QFN 23 is a smallpackage arranged with plural lead parts (lead) 21 d to be externalterminals in an exposed state for the back surface peripheral part ofthe sealing body 4 as shown in FIG. 27.

In the QFN 23, too, as shown in FIG. 28, the semiconductor chip 1 andplural wires 7 are sealed with resin by the sealing body 4. The formingmethod of the sealing body 4 is exactly the same as that of the sealingbody 4 of the BGA 9 in accordance with the embodiment 1. It is becausethe rear surface of the die pad 21 a is exposed in the rear surface ofthe sealing body 4 as shown in FIG. 27 to give such structure that noresin flows into the rear surface side of the die pad 21 a.

Accordingly, in the molding of the assembling of the QFN 23, too, theresin sealing is performed by using the same die as the resin moldingdie 13 in the embodiment 1 in FIGS. 11 to 16. In the resin filling, thestate shown in FIGS. 17 to 20 is given to allow to push out the void 12contained in the resin into air vents without allowing the void toremain in corner parts of the cavity 14 a.

Consequently, like in the BGA 9, the occurrence of the void 12 can beprevented in the cavity 14 a. The formation of a void can be preventedin the sealing body 4.

As a result, the occurrence of the appearance defect of the QFN 23(semiconductor device) can be prevented. The yield of the QFN 23 canimprove. Moreover, because the occurrence of the appearance defect ofthe QFN 23 can be prevented; the quality of the QFN 23 can improve.

Other effects given by the QFN 23 are the same as effects of the BGA 9in the embodiment 1. The repeated explanation is omitted.

The invention by the present inventor is, explained specifically inaccordance with the embodiments of the invention. The present inventionis not limited to the embodiments of the invention and can be changedwithin the scope that does not deviate from the purport.

In the embodiments 1 and 2, the case that the upper die 14 is the firstdie and the lower die 15 is the second die in the resin molding dies 13and 22 is explained. If the upper die 14 and the lower die 15 are apair, either of them may be the first die or the second die.

Further, in the embodiment 1, the die shown in FIG. 12 and FIGS. 14 to16, the radius r2 of the cross section of the second corner part 14 f ofthe cavity 14 a is the same as the radius r3 of that of the third cornerpart 14 g (r2=r3). All the cross sections of inner peripheral surfaces14 b of the corner parts (the rB part, the rC part, the rD part, the rEpart, the rF part, the rG part, the rH part, and the rI part) of thecavity 14 a forming edge parts including side surfaces and the uppersurface 4 a of the sealing body 4 in FIG. 1 are formed with the size ofthe radius r2 in FIG. 14 (also may be the radius r3 in FIG. 16). In thecavity 14 a of the resin molding dies 13 and 22 of the embodiments 1 and2, at least the radius r2 of the cross section of the inner peripheralsurface 14 b of the second corner part 14 f (the corner part over theair vent in the position most separate from the injection gate 14 d) islonger than radii of cross sections of inner peripheral surfaces 14 b ofother any corner part, radii of cross sections of inner peripheralsurfaces 14 b of corner parts (the rB part, the rC part, the rD part,the rE part, the rF part, the rG part, the rH part, and the rI part) arenot necessarily the same as the radius r2.

Copper is harder than gold. When a copper wire with the same diameter isa gold one is used as the wire 7 instead of a gold wire, the copper wireis more resistant to the wire displacement. When copper wires becomethinner, a countermeasure for the wire displacement is necessary. Thedescribed characteristics are effective in solving the problem.

The present invention is suitable to assemble electronic devices using aresin sealing method.

What is claimed is:
 1. A method of manufacturing a semiconductor devicecomprising: (a) preparing a wiring member having a top surface overwhich a semiconductor chip is mounted, (b) disposing the wiring memberon a die surface of a resin molding die having a cavity such that thesemiconductor chip is located in the cavity of the resin molding die,and (c) forming a sealing body resin-sealing the semiconductor chip byinjecting a resin into the cavity of the resin molding die, wherein thecavity of the resin molding die has a bottom surface, a first sidesurface, and a second side surface, a radius of an inner arc composed ofportions of the bottom and first side surfaces being longer than aradius of an inner arc composed of portions of the first and second sidesurfaces, and wherein after the step (c), the sealing body has a topsealing surface, a first sealing side surface, and a second sealing sidesurface respectively formed by the bottom, first side, and second sidesurfaces of the cavity of the resin molding die, a radius of an innerarc composed of portions of the top sealing and first sealing sidesurfaces being longer than a radius of an inner arc composed of portionsthe first and second sealing side surfaces.
 2. A method of manufacturingthe semiconductor device according to claim 1, wherein a radius of aninner arc composed of portions of the bottom and second side surfaces ofthe cavity of the resin molding die is longer than the radius of theinner arc composed of portions of the first and second side surfaces ofthe cavity of the resin molding die, and wherein after the step (c), aradius of an inner arc composed of the top sealing and second sealingside surfaces of the sealing body is longer than the radius of the innerarc composed of portions of the first and second sealing side surfacesof the sealing body.
 3. A method of manufacturing the semiconductordevice according to claim 1, wherein an air vent is formed at the firstside surface of the cavity of the resin molding die.
 4. A method ofmanufacturing the semiconductor device according to claim 1, wherein thecavity of the resin molding die is substantially quadrangle shape in aplan view, a first corner potion of the cavity has a chamfer, thechamfer is the first side surface.
 5. A method of manufacturing thesemiconductor device according to claim 4, wherein the cavity of theresin molding die has a second corner portion opposite the first cornerportion in a direction of a diagonal line of the cavity, and wherein inthe step (c), the resin is injected into the cavity from the secondcorner portion.
 6. A method of manufacturing the semiconductor deviceaccording to claim 1, wherein the wiring member is a wiring substrate.7. A method of manufacturing the semiconductor device according to claim6, further comprising: (d) after the step (c), disposing a plurality ofsolder balls over a bottom surface opposite the top surface of thewiring member.